Thus far, an inductively-coupled plasma torch has become well known as a method of generating a high-density thermal plasma in the atmosphere. In the method, high-frequency power is supplied to coils wound on the outside of a cylindrical dielectric chamber so as to generate thermal plasma in the dielectric chamber (for example, refer to Patent Literature 1, Non Patent Literature 1, and Non Patent Literature 2). The inductively-coupled plasma torch is used for plasma spraying, thermal treatments, powder synthesis, element analysis, and the like.
Additionally, a variety of relevant techniques have been disclosed (for example, refer to Patent Literature 2 to 4). For example, Patent Literature 2 discloses a high-frequency atmospheric pressure low-temperature capacitively-coupled plasma (CCP) apparatus that pulse-modulates high-frequency power. Patent Literature 3 discloses a vacuum low-temperature plasma ICP apparatus that pulse-modulates high-frequency power. Patent Literature 4 discloses a vacuum ion injecting apparatus that pulse-modulates high-frequency power.